Fire detector



July 18, 1944. A. J. GARDENHOUR 2,35411 FIRE DETECTOR Filed Dec. l, 1942//e/ J Garden/your,

Patented July 18, 1944 f f UNITED Thisinvention relates to improvementsin-fire alarm systems and apparatus. -f

The primary object" of this invention-is the provision of arelativelyeconomically constructed fire alarm system which is foolproof and whichwill elimina-te the necessity of'providing watch'- men and expensivesprinkler systems. V y Other objectsl and advantages of this inventionwill be apparent during the course of the following detaileddescription. f

In the accompanying drawing", formi-ng a part of this specification, andwherein similar'reiference characters designate c'orrespondingparts:

thruout theseveral views,

j Figure lis a `perspective view ofy afnormally closed switch unitassociated as p art'of' the' ,fire alarm apparatusl f u M j f Figure 2is a longitudinal cross sectional View taken thru the `unitof Figure 1,and showing the detail'sof construction thereof. Figure 3isadiagrammatic representation of a circuit'in which the unit ofFigure'lis used.

`In'the 'drawing,lwherein for .the purposeof lllustration is shown onlya ypreferred embodiment of vthe invention, theletter A maygenerallydes`A ig'nate the improved re alarmsyst'em whichmay include a pluralityof the units B. ,A n I.

The units B, which may. appropriatelyf be termed fire detectors, areadapted to be mounted uponthe ceiling or wallsof the building to beequipped with the re alarm system, preferably one to eight square feetof the wall section. They are arranged in series and constitute a closedswitch in anormally closed circuit to be subsequently described.

Each unit B preferably consists of a ilat base I0, of some approvedinsulation material, preferably synthetic resin, upon which detachablebinding post constructions II and I2 are mounted at the ends thereof.Each of these binding post constructions preferably consists of a postbody I3 having lower and upperl axially disposed screw threaded openingsI4 and I5 therein. Each lower screw threaded opening I4 is adapted toreceive the screw threaded shank of a countersunk head screw I5 by meansof which the post body is positioned upon the base IU normal to the topsurface thereof. These post bodies I3 are preferably of brass or someother approved metal, and between the lower ends thereof and theinsulation base IIB, they detachably clamp metal terminals I1 upon thebase. These terminals Il are of the jaw type for clamping of an end of awire therein, and of course they extend laterally of the post bodies I3,preferably in right angled Irelation with respect to a line drawnbetween the two 'ports II and I2. f

. Two stamped sheet metal links' or members 20 and 2I are provided;theformer having an opening 22 in the largerend thereof adapted toreceive the shank of a cap screw 23 by means of whichv the flink c'anbeclamped uponthe Post body I3`-of the Ibindingpost I I in the mannershown in Figurek 1* 'of the drawing. :The other link 2l is provided withan opening' 24 atits larger end adapted tore/ceive'one end of a coilspring 25. The 1other end-of the coil spring 25 is adapted to be clampedupon the top of the binding post body I3"by'rneans"-of aI'at-.washer2li. and a cap screw 2l.' The screws23` and 2l, of course, are screwthreaded axiallyjinto the binding [post bodies I3. lThelinks 2l)`r and2l yare flatand taper from theiryremote endsin reducedrelation towardstheirfproximate ends where' they are apertured afnd adapted'toreceiveapinfrivet or connection 3D f'II'iSib ematerial, such as solder.

11n the" sition shown in Figures 1 and 2, the coil "spring, 2,5isyfurder tension so that when abnormall'temperaturesare created in thevicinity ofE theffusiblfe rivet SQILthe/same Will melt andthel'spring,.of,course, `will.separate the links 2U and2I-'fforbreakingfthefnormally closed circuit in whichftheunitsB areplaced. 0i' courser fusible material may.beplacedlbetween the proximateens1s-ffiher1mks2andere so desired- Referring to the Wiring arrangementof the system A, as before mentioned, the units B are placed in series,as shown in Figure 3. A magnetic relay 35 is employed. It has a wire 3Gleading off from its winding connected to one end of the series of unitsB; the other end of the winding being connected by wire 38 to lowvoltage secondary 39 of a transformer 43. The wire 4I leading from thissecondary 3! is connected to the other end of the series of units B.'The source of current is established on the primary winding 4I of thetransformer 451, and of course the current is completed thru thesecondary winding 39 the closed units B, and the relay The latter isthus energized and attracts an armature 46 which is normally pivoted at41. In this position the armature 46 engages a Contact 48 of a wiringcircuit 49 wherein is employed a pilot light 5I). This circuit 49 ofcourse includes the armature 46 as a part thereof and the source ofcurrent is indicated in Figure 3.

An alarm 52, which may be in the nature of a siren, has one of itscontacts in the circuit 49 and its other terminal ending in a contact.53

normally spaced from the armature 46. A spring 54 normally urges thearmature 46 so that when the relay 35 is deenergized, the armature 46will engage the contact 53 and close the circuit thru the siren or alarm52.

It will be apparent from the foregoing, that the low voltage powersupply is constant in the secondary winding of the transformer, and thecircuit thru the units B is normally closed, Upon abnormal elevation oftemperatures the solder or fusible alloy of the units B will melt andbreak the circuit. This releases the armature and sounds the alarm.

While I have shown the re detector system as operated from an outsidesource of supply, such as 110 volts A. C., it is possible to utilize aninternal battery source of supply which is so arranged as to work relayan alarm either from a batteryY unit or direct current.

Various changes in the arrangement of the system, and in the shape, sizeand arrangement of parts thereof may be made to the form of inventionwithout departing from the spirit of the same or the scope of theclaims.

I claim:

l. In a fusible switch unit for re alarm systems the combination of aflat insulation base, a pair of upstanding detachable binding postsmounted upon said base in spaced relation, terminal clips connected bysaid binding posts directly upon the top of said base, a pair of links,fusible material connecting proximate ends of said links, meansconnecting one of said links in direct contact with the upper end of oneof the binding posts, and means placing said links under tension andconnecting the remote end of the other link to the other binding post innon-contacting relation therewith.

2. In a normally closed fusible switch unit for fire alarm systems thecombination of an insulation base havinga pair of relatively spacedopenings therein, a pair of binding post bodies having screw threadedopenings in the lower ends thereof and screw threaded openings in theupper ends thereof, screws detachable from the bottom of said baseextending thru the openings in said base and into the screw threadedopenings at the lower ends of said posts for detachably connecting thesaid posts in right angledupstanding relation upon said base, laterallyextending-electric wire attaching spring terminals clamped upon the'topof said base by the lower ends of said posts as an incident ofattachment of the posts by said screws to said base, a pair of elongatedconnecting links, a fusible alloy connecting the extreme proximate endsof said links, one of said links being disposed over and in contact;with one of the binding posts, a screw detachably connecting said linkto the top of said binding post, a coil spring, a screw connecting oneend of said coil spring upon the top of the other binding post, theopposite end of said coil spring being connected with the other link andbeing under tension to normally move said links apart upon melting ofthe VVfusible material connecting said links.

3. In a normally closed fusible switch unit for re alarm systems thecombination of an insulation base, la pair of binding posts mounted uponVsaid base and extending upwardly normal thereto,

a sheet metal link rigidly and detachably mounted in direct contact withone of said binding posts, a metal spring connected in electricalcontact with the other binding post having a horizontally disposed coil,a sheet metal link connected with the opposite end of said spring, andfusible material connecting the proximate ends of said links so as tomaintain said horizontally disposed coil spring under tension.

4. In a normally closed fusible switch unit for fire alarm systems, thecombination of an insulation base, a pair of metal binding posts mountedin upstanding normal position upon the top of said base, a pair ofelongated fiat sheet metal links each having openings in each of theends thereof, a screw inserted thru one end opening of one of said linksand threaded in the top of one of said binding posts and clamping saidlink in laterally extending relation upon the said binding post parallelwith the plane thereof parallel with the top surface of said base, afusible rivet-like member in the other opening of said link and thru oneof the openings of the other link for connecting said links, ahorizontally positioned tensioned coil spring having one end connectedto the other of said binding posts and its other end inserted in theother opening of the second mentioned link for holding said links undertension, the said mounting of the second link also positioning it withthe plane thereof parallel with the top surface of said base.

ALLEN J. GARDENHOUR.

